Indications and Duration of Therapy
Recommended Therapeutic Range and Duration of Therapy with Warfarin
Adapted from the 9th Edition of the CHEST guidelines:
| Antiphospholipid Syndrome |
2.0-3.0 |
indefinite (2B) |
| DVT and PE |
| Transient/reversible risk factor |
2.0-3.0 |
3 months (1B) |
| Unprovoked |
2.0-3.0 |
at least 3 months (1B) then reevaluate |
| Second episode of unprovoked |
2.0-3.0 |
extended (1B) |
| Non-Valvular Atrial Fibrillation/Atrial Flutter |
| CHADS2 = 0 (low CVA risk) |
N/A |
no therapy (2B) or ASA 75-325mg (2B) |
| CHADS2 = 1 (intermediate CVA risk) |
N/A |
dabigatran (2B) |
| CHADS2 ≥ 2 (high CVA risk) |
N/A |
dabigatran (2B) |
| With mitral stenosis |
2.0-3.0 |
long-term (1B) |
| With stable CAD |
2.0-3.0 |
long-term (2C) |
| Prior to/following cardioversion to NSR |
2.0-3.0 |
3 weeks/4weeks (1B) |
| Mechanical Heart Valve |
| Aortic |
2.0-3.0 |
long-term (1B) |
| Mitral |
2.5-3.5 |
long-term (2C) |
| Bioprosthetic heart valve |
| Aortic |
N/A |
aspirin 50-100mg (2C) |
| Mitral |
2.0-3.0 |
3 months then switch to ASA (2C) |
Reference:
Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines 2012
Strength of Recommendations Grading System
From the 8th edition of the CHEST guidelines:
| Antiphospholipid Syndrome |
| No additional risk factors |
2.0-3.0 |
indefinite (1A) |
| Recurrent events with therapeutic INRs |
2.5-3.5 |
indefinite (2C) |
| DVT and PE |
| Transient/reversible risk factor |
2.0-3.0 |
3 months (1A) |
| Unprovoked |
2.0-3.0 |
at least 3 months (1A) then reevaluate (1C) |
| Second episode of unprovoked |
2.0-3.0 |
long-term (1A) |
| After 3 months at 2.0-3.0 |
1.5-1.9 |
long-term (1A) |
| With active cancer after LMWH for 3-6 months |
2.0-3.0 |
indefinite (1A) or until CA resolved (1C) |
| Atrial Fibrillation/Atrial Flutter |
| With prior CVA/TIA or systemic embolism |
2.0-3.0 |
long-term (1A) |
| CHADS2 = 0 |
N/A |
aspirin 75-325mg (1B) |
| CHADS2 = 1 |
2.0-3.0 |
long-term (1A) or aspirin 75-325mg (1B) |
| CHADS2 ≥ 2 |
2.0-3.0 |
long-term (1A) |
| With mitral stenosis |
2.0-3.0 |
long-term (1B) |
| Following open heart surgery |
2.0-3.0 |
4 weeks (1B) |
| Prior to/following cardioversion to NSR |
2.0-3.0 |
3 weeks/4weeks (1C) |
| Mechanical Heart Valve |
| Aortic bileaflet or tilting disk |
2.0-3.0 |
long-term (1B) |
| Mitral bileaflet or tilting disk |
2.5-3.5 |
long-term (1B) |
| Aortic or mitral caged ball or caged disk |
2.5-3.5 |
long-term (1B) |
| Any valve with additional risk factor |
2.5-3.5 |
long-term (1B) |
| Any valve + suffer embolism with target INR |
increase + add ASA |
long-term (2C) |
| Bioprosthetic heart valve |
| Aortic |
N/A |
aspirin 50-100mg |
| Mitral |
2.0-3.0 |
3 months then switch to ASA (1B) |
| With prior h/o systemic embolism |
2.0-3.0 |
3 months then reassess (1C) |
| With LA thrombus |
2.0-3.0 |
until resolution (1C) |
| Cardioembolic Ischemic Stroke |
2.0-3.0 |
long-term (1A) |